In this specification where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge, or otherwise constitutes prior art under the applicable statutory provisions; or is known to be relevant to an attempt to solve any problem with which this specification is concerned.
Acoustic imaging, such as ultrasonic imaging, has been used in various material testing or measurement applications. For example, ultrasonic imaging has been used in non-destructive testing applications such as the testing of the properties of manufactured materials (e.g., testing for corrosion in aircraft wings). Acoustic imaging has further been used in medical imaging applications such as human soft tissue diagnosis. Some conventional systems used to perform ultrasonic testing have suffered from a number of disadvantages, such as system complexity and lack of image resolution.
The ultrasonic imaging systems and techniques described in U.S. Pat. No. 6,552,841, the entire contents of which is incorporated herein by reference, represent an advance in the state of the art. The systems and techniques described therein generally include a source transducer, typically formed from a ceramic-based material, which produces an unfocused beam that is then passed through a beam splitter on its way to the target. Both pass-through and reflection modes of operation are described. Thus, the systems and techniques described therein further include a sensor which receives acoustic energy which is either reflected off of, or passed through, the target being imaged.
U.S. Pat. Nos. 5,406,163 and 5,283,438 describe detectors that are formed, at least in part, by a polyvinylidene fluoride material.
Despite the above, there is still a need in the art for improved acoustic imaging arrangements and techniques.